Method of lining brake drums



April 16, 1935. w. H. FARR 1,998,047

METHOD OF LINING BRAKE DRUMS Filed July 12, 19-30 1 3 Sheets-Sheet 1 4FIG. 5 INVENTORQ I Wm H We April 16, 1935. w. H. FARR 1,998,047

METHOD OF LINING BRAKE DRUMS Filed July 12, 1930 s sheets-Sheet 2 vINVENTOR. M9525 /1 H922 T166. I yaww ATTORNEY,

April 16, 1935. w, FARR 1,998,047

METHOD OF LINING BRAKE DRUMS Filed July 12, 1930 5 Sheets-Sheet 5 v I II 2 7 F 1 5 INVENTOR.

- 5 Y I ATTORNEY.

PatentedApr. 16, 1935 r I j j I Q UNITED-7ST TET OFFICE 1,998,047 METHODor LININGBRAKE DRUMS hen H. Farr, Detroit, Mich, assignor to Budd WheelCompany, Philadelphia, Pa., avcorporation of Pennsylvania j ApplicationJuly 12, 1930, Serial No. 467,535

I V '3 Claims. (Cl. 29152.2 v The invention relates to brake drums andthe and drum to' lock them against relative move: like and a method oflining such drums by a suit ment in all directions. This refinement ofthe able wearresisting lining to increase their.life; invention isnot'necessary in all cases, since the It is an object of the inventionto provide such hammering eiiects, such an intimate molecular a drum inwhich a wear resisting linen-is very interlock between the molecules ofthe liner. and 5 intimately united with the-.main body of the thesurface of the drum," as to preclude relative drum so as to lock itthereto, and. to provide'an shifting under most normal conditions ofusage. inexpensive and efi'icient method of so uniting. Also the surfaceof the sheetsjiout of which brake the liner to the drum surface, g'drums'are ordinarily formed have sufficient surlo Liners ofwear-resisting qualities have heretoface irregularities inmost oases,toefiecttheine fore been applied to the braking face by variousterlockrequired without any additional roughenexpedients, such asheating and shrinkingin ing' treatment such as is above-specified;Anplace, casting the brake drum onto the'lining, otheruadvantageouseffect of the'haimme'ring is and rolling the lining into the drum. Noneof that it hardens the liner'an'd th Q B f these methods has produced adrumin which-the life. A I v 1 lining and drum were intimatelymolecularly in- The'metl'iod maybe used n ma the JIIS terlockeci and atthe s'ame time, the face of the originally 'or in reliningused drums, orit may be lining was accurately sized and trued atone and 1l cdin0Dating up other Work, hanbrak the sameoperation, someof these m th d 33-drums, in whichliners ofthis class are desirable.

ac quired heattreatment either before or afterlap- 1" In theaccompanying "drawings, there areillusplication, and machining or otheroperations trated more or less diagrammatically, several after the heattreatment to reduce the braking Ways i whi the method ma be p c e bu uface". to true and accurate form and size. it will be understood thatthe showing is merely Othersnot requiring heat treatment, did notacillustrative, as it will be obvious to those skilled complishtheintimate interlock required to prein the art that the'invention iCapable 9 being 25 I 'vent'loosening of the lining, before or after acarried out in different Ways. I period of use. p In the drawings, HThese difliculties are overcome and the objects 'FigS- 1 and 2 are e tvel a s d elevaof the invention attained by applying the lining tionalview and an axial sectional view of a brake '30 to the surface tobetreated and then hammerdrum lined in accordance withthe invention.

ing it so as 'to deform it internally to cause a r Fig. 3 is. atransversesectional View showing molecular interlock between the surfaceof'the more or less diagrammat ca ly, ap u f lining and. the brake drumproper, the hammerswaging' the, lining in place in the inner peripheraling at the same time being carried out in a mana f t drumr l f ner tocausea final surface on the lining which Figs, 4 and 5 are detail axialsectional view .5

is a true cylindrical surface of revolution and showing the W before andafter being SWaged accurately sized. Tothis end, the inventionfurinits'relatio'n to the adjacen Parts of t Sw ther comprehends. therelative rotation of the i gapp a t V v work and the hammering meanswhile the ham- F g '7 and 8 are detail axia sectional Views .40 Ineringis taking place,and, in order to balance of amodificati ni v v et p m ay f rmthe forces,'the simultaneous hammering of oping'in the innerSurfaceof the drum of a n posed endsof a diameter or the work. The hamdre s s, 6 illustrating a too act o the mering at an instant takesplacealong 'a small Work, Fig- 7, illustratin'gthelinel in Pl bef r are orarcs, but the relative rotation of the-work the sWaging, and Fig. 3illustrating the liner 4:5 and hammering means results finally in acomswaged in place. c I plete treatment of a surface of revolution, and.F g. 9 is an inside elevational view Show One a reduction to true andaccurate size; To'jiurmethod of securing the liner in placebefore'swagther aid in providing an interlock, the invention ing it inplaceJ contemplates, in some instances, the preliminary Fig. 10 is anaxial section of a -modified brake V 0 roughening of the surface to betreated, either drum with the linerin'place before swaging'the win byforming depressions or elevations therein, or liner-in place;

both with; which a portion of the metal of the I Figs. i1, 12and 13 ar alaxialsectionsil usliner, when interiorly deformed by the hammertratingthe method used in forming the modified ing operation, is adaptedtc forma very secure .:bral e; drum shown in Fig. 9 and in swagingitin'interlock between the adjacent faces of the liner place, Fig. llshowingthe step of forming the v annular ribs on the inside face of the drum byswaging, Fig. 12 showing the lining in place before swaging it in place,and Fig. 13 showing the lining swaged in place.

Fig. 14 is a detail perspective view. of a hammer which can be used inthe swaging operation shown in Fig. 11. V

Fig. 15 is a detail view of a drumformed with both circumferential andaxial depressions prior to the application of the lining.

A form of brake drum resulting from the practice of the invention isshown in Figs. 1 and ,2as having the radially extending attaching flange10, the outer peripheral cylindrical brake surface portion El and thestiffening edge. flange l2. Within the inner peripheral surface of theportion I l is shown secured the wear resisting lining I3 made of amaterial, such as high carbon steel having long wearing qualities. thislining is securely locked against axial displacement or rotation, byJthemolecular interlock between the surface of portion 'I i and the lining,even without preliminarily. roughening the ,surface on portion H. Thesurface of the metal, such as low, carbon steel, out of which brakedrums are ordinarily drawn has sufficient minor irregularities betweenthe molecules thereof; to cause the molecules of the lining, under theheavy working effected in the process of hammering the lining in placeby the improved method, to lock the lining securely in place bymechanical as well as molecular interlocking.

ln'thepractice of my method, the lining I3 is in the'form of an annulus,which may be con' tinuous and formed by bending a fiatstrip into a hoopand butt welding the ends together or may be cut into a length tosubstantially fitthe face of the. drum which it is'desired to line whenbent into a hoop, is inserted, either in this'welded together annularform, as shown, or in the form of an annulus having its ends abuttingbut not integrally joined, within the inner peripheral face of portion II of the'drum, where it may be tacked inplace by spot welds as shown inFig. 9, to hold it in place preliminarily'to the swaging operation.

The assembled drum and lining is then placed in a swaging apparatus suchas that shown in Fig. 3 comprising'an outer series of work holdingclamps 54 supporting the external peripheral .surface'of the work andacting as a substantially continuous anvil surface 15 backing up thesaid face of .the drum under the hammer blows delivered to the interiorperipheral surface of the lining by, suitable means. Such means maycomprise the radially movable hammers l6 havng relatively narrow arcuatesurfaces J! to engage 'the work, andmounted in an annular swaginghead l9axially aligned with the work'holding clamping means. Axially of theswaging head is arranged actuating means for'the hammers comprising ashaft l8 adapted to'be rapidly rotated in the head and carrying anannular series-of rollers 26 arranged in spaced arrangement about theaxis. The rollers20 are also radially movable to aslight extent and arefrustoconical in form, and adapted to be supported on their inner sidesand fed into the work, by a coni- From an inspection of Fig. 3 it willbe seen that when the work'a'nd swaging head are relatively rotated,and'tlie shaft'Zl is rotated, the rollers will successively engage thearcuate'ribs 22 on'the inner sides of the hammers and throw thesame'outwardly to delivera succession of blows with great rapidity againstthe By the method inner face of the lining to expand it around itsentire circumference'and to intimately interlock it with the face of thedrum. The hammers are 1 preferably arranged in pairs at opposite ends ofa with the face of the drum.

While it has been found ordinarily that a sufficiently strong interlockis obtained under all ,conditions of operation, without anypre-treatment of the surface of the brake drum to be -1ined, it may bedesirable in some cases, to additionally roughen the surface againstwhich the lining i's swaged. g H To carry out this feature, Fig. 6showsthe step of forming a series of annular grooves 23 in the innerperipheral face of the drum while-rotating it in a work holder and theuse of a cutting tool 24. After the grooves have been formed, the liningis inserted, as shown in Fig. 7, and by the. swaging operationillustratedin Fig. 8, it is expanded to fill the "grooves, thus verysecurely locking itin place. The use of a tool, as 24', leaves a numberof bins at the edge of the grooves which interlock mechanically with thelining to furtherlock the lining against rotation. 7

According tothe form of the invention shown in Figs. :9 to 13, thesurface to be lined is preliminarily treated to form a series of annularribs 25 in said surface, and thismay be done by a swaging operationsimilar to the final swaging of the lining in place, but by the use ofhammers 26 having a work engaging insert 27 grooved correspondingly tothe ribs to be formed in the brake surface. Fig. 10 shows thispreliminary swaging operation, Fig. 11 shows the insertion of thelining, and Fig. 12, the final swaging operation showing theliningswaged in place and interlocked with the ribs 25.

The particular manner in which the depression and projections areformed, and their "direction and extent is immaterial for carrying outthe broad features of the invention, and the specific means employed toform them and the specific grooves and ribs formed are merelyillustrative of the apparatus which may be used and the form which theroughing of the surface as applied tothe lining of internal peripheralbraking surfaces, it may also be applied to the lining of externalperipheral surfaces, and other and further modifications anddifferentiations may be employed by'those skilled in this art withoutdeparting from the spirit and scope of the'invention as defined'in theclaims appended hereto.

What Iclaim is? V 1. The method of lining brake drums whichcomprisesapplying a liner to the brake cylinder and simultaneously cold'swaging said liner tothe cylinder over small areas at opposite ends ofsuccessive diameters along substantially the total axial depth of theliner, whilerelativ'ely rotating the work and hammering the linerandthe'cylinder together to intimately unite and interlock 7 them in alldirections against displacement tendencies of the braking operation.

2. The method of locking a brake lining to a brake cylinder againstbraking-displacing efiects, and simultaneously hardening the brakingsurface of the lining to resist braking wear, which comprisestelescoping the lining and the cylinder into snug fitting relation,setting up a rotary motion about the cylinder axis, and. deriving fromthe rotary motion an annular series of simultaneous oppositely directedreactionary rectilinear radial blows successively about said axis onsmall areas of the braking side of the lining.

3. The method of assembling a brake surface liner to a brake drum andlocking the liner to the drum cylinder against peripheral and axialdisplacement from the cylinder, which comprises providing the cylinderwithshoulders resisting such displacement, setting up a rotary motionabout the drum axis, deriving'repeated equal and opposite sets of radialforces from said rotary motion, and utilizing the forces of said set toefiect hammer blows over small areas of the braking surface to harden itand to lock the liner to the drum cylinder relative to said shoulders.

- WARREN H. FARR;

